Tips & Tutorials

Update Galaxy S3 I9300 to JellyBam 4.2.1 Jelly Bean Custom ROM

You can now enjoy Android 4.2.1 on Galaxy S3 I9300 with this amazing new custom ROM, JellyBam which is based on the latest Android 4.2.1 Jelly Bean. We are yet to receive an official update from Samsung that is based on Android 4.2.1, so till then we can enjoy Jelly Bean with this custom ROM. This is a custom firmware for the Samsung Galaxy S3 I9300 which combines CyanogenMod and AOKP altogether and offers a whole new experience which we think you would adore.  You can update Galaxy S3 I9300 to JellyBam Android 4.2.1 Jelly Bean ROM custom firmware using the tutorial below.

As you continue reading below, we will guide you through the entire process of how to install JellyBam Android 4.2.1 Jelly Bean on Galaxy S3 I9300 with complete steps. Don’t forget to read all the tips below that you have to keep in mind before proceeding. ClockworkMod recovery should be already installed on your Galaxy S3. Please make sure you backup all your data as given below because this tutorial will wipe your data. Let’s get to the tutorial now.


Disclaimer: All the custom ROMs and firmwares, official software updates, tools, mods or anything mentioned in the tutorial belong to their respective owners/developers. We ( or the developers are not to be held responsible if you damage or brick your device. We don’t have you on gun point to try out this tutorial 😉

JellyBam Android 4.2.1 Features:

For a quick look at what features are offered by the JellyBam ROM, read the long list below:

  • Built from source
  • Overall features of AOKP, CM10.1
  • Custom JellyBam Settings with preferences
  • Tons of customizations
  • Themes and Mods in JellyBam style
  • Latest CM10/AOKP Kernel compiled from sources
  • Google apps included
  • New Mali driver
  • Exynos HWComposer
  • Lockscreen with x8 Custom app targets
  • Bravia Engine libraries
  • Bravia XLoud audio libraries
  • PerApp DPI XPosed settings
  • CM 10.1 Chronus widgets
  • Infinite widgets on lockscreen
  • Custom home action and hardware button in lockscreen
  • Quick/Long click on weather and clock actions
  • JellyBam Panel in settings app
  • AOKP and CyanogenMod Settings
  • Mass storage mode
  • OTA Update via UpdateMe App
  • GAPPS included, no need to flash anything else
  • Apollo Music Player (Themed)
  • Quick SMS
  • AwesomBeats Lib
  • A good combination of stability and performance (Thanks Siyah Kernel + Personal mod)
  • Bluetooth hacked for send / receive APK
  • YouTube hacked with 3G+WiFi HD 720p PlayBack
  • Init.d scripts
  • JellyBOOM script
  • Media quality tweak
  • 3G and GPS Tweak
  • RAM Optimization + Multitasking
  • SmoothScrolling tweak
  • V6 Supercharger included
  • lot of Themes available in UpdateMe
  • TouchWiz 5 Launcher
  • Trebuchet Launcher
  • *Beats Audio by Dr Dre*(Powerfull bass)
  • Clearbass Sound by Sony*(Clear Bass)
  • Xloud by SonyEricsson*(higher sound volume and clearer sound on speaker)
  • Dolby Digital Sound*(Equalizer enhancer bass setting and Surround setting)
  • Surround Sound*(Deeper bass and reduction of bass distortion plus Eq setting support)
  • JellyBam custom Bootanimation by metallaxis
  • Center Clock/No clock/Right Clock
  • Volume Panel (Volume Rocker allows you to change ALL volume levels in one Menu)
  • Lockscreen Weather
  • Lockscreen Vibration on/off toggle
  • Performance/Color Settings
  • Brightness Control Slider
  • Multilang
  • JellyBam Style

You might want to read these:

Samsung Galaxy S3 USB Drivers

You will need to connect your Android phone with the computer. For that, please make sure you have installed the USB drivers for Samsung Galaxy S3 properly. If not, you can download the latest official drivers from our Android USB Drivers section here:

Download Samsung Galaxy S3 USB drivers!

Backup and Other Important Tips

Done with the USB drivers? Perfect. The tutorial is on the next page, but first, please take a look at the following tips and important points you need to take care of. These are important, as we don’t want anyone losing their personal data or apps:

Always backup your important data that you might need after you install a new custom ROM, an official software update or anything else. Make a backup for just in case, you never know when anything might go wrong. See below for some tips on how to backup data:

Samsung users can also back up data using Samsung KIES. If you backup data manually, you get more options what to choose from and it is very easy to move data across Android devices from different manufacturers, i.e moving Samsung Galaxy Note backup data to HTC One X.

If you already have a custom recovery (ClockworkMod, TWRP etc.) installed on your phone, we strongly recommend a backup using that as it creates a complete image of your existing phone set up.

A few more optional tips that you should remember:

1. Having problems connecting your Android phone to the computer? You need to enable USB debugging mode. See here: How to Enable USB Debugging — for Gingerbread, Ice Cream Sandwich and Jelly Bean.

2. Make sure your Android device is charged up to 80-85% battery level. This might help you: How to Check Battery Percentage. Why? Because, if your phone goes off suddenly while installing a custom ROM, flashing an official firmware update or installing mods etc. — your phone might get bricked or go dead permanently. No one wants that, right?

4. Most of the tutorials and how-to guides on Team Android are for factory unlocked Android phones and tablets. We recommend NOT to try our guides if your phone is locked to a carrier, unless we have specified the carrier name or device model.

If you find the above tips useful and they were helpful to you, please consider giving us a +1 or LIKE to thank us!

All set and ready? Good. Now, let’s proceed with the tutorial on the next page and update Galaxy S3 I9300 to JellyBam Android 4.2.1 Jelly Bean custom firmware.